Motor vehicles demand small outer dimensions, large inner space, strong drive lines and a high level of equipment. The distance of collapse in the engine compartment during a crash is limited because of these demands. During a frontal crash, the front side members are compressed in order to absorb energy and keep the crash pulse low.
It is known that when a motor vehicle is subject to a large force such as a frontal impact, the vehicle structure and components are often displaced or deformed into the occupant area. This is potentially dangerous as it may result in injuries to the driver and passengers.
In general, vehicles, such as a motor vehicle, are equipped with a suspended brake pedal. This brake pedal is suspended on a dash panel by a pedal bracket. The dash panel is partitioning the vehicle into an engine compartment or room in front of the vehicle and a passenger compartment. The brake pedal is normally constructed such that it extends to the rear of the vehicle.
Further, the instrument panel is a vehicle body component disposed adjacent to an engine in the engine compartment. Therefore, during a frontal collision of the vehicle, the engine can move toward the rear of the vehicle and push the instrument panel into the passenger compartment. This causes the instrument panel to deform and stick-out toward the rear of the vehicle. Consequently, the brake pedal can move toward the rear of the vehicle.
The arms on a brake pedal are very rigid such that an operator can operate the brakes. Likewise, an arm on a clutch pedal is also rigid in order to perform its designated task. Such rigid arm structures are potentially damaging in the event of interaction with a human being at the time of a crash.
In particular, if an operator is using a pedal at the time of a crash, there is a risk that the pedal arm will be pushed rearward by the impact, causing the included angle between the upper surface of a foot of the operator and a leg, to which the foot is attached, to be reduced. This reduction in angle is likely to cause injury to the ankle joint connecting the foot and the leg.
Furthermore, when the front part of the vehicle is deformed, it is common that the driveline hits a brake booster, which is then dislocated rearward in the vehicle. The brake booster is typically attached to the brake pedal arm through a pushrod. If the pushrod is moved rearward equally as much as a center movement of the pedal, the pedal plate for the foot of the driver will move rearward in the same proportion, and will not typically result in injury to the operator. However, if the pushrod moves rearward more than the brake pedal, the pedal plate will move rearward more than the upper part of the brake pedal arm. This movement will usually be geared up at a ratio of approximately four to one. This may occur if the brake booster is dislocated more than the upper part of the pedal box. This may cause injuries to a lower leg of the operator.
Furthermore, if the brake booster is hit mainly at one side, this side might leave a higher intrusion than the other, which may have the consequence that the pedal box and the brake pedal arm will be slanting. This may also cause injuries to a lower leg of an operator.
Some previous attempts to reduce the risk of crash injuries caused by the brake pedal are based on the concept of releasing the brake pedal arm, such that it is not possible to displace it further to the back of an associated vehicle.
One such previous attempt is illustrated in US 2004/0020324, which describes a brake pedal assembly for a motor vehicle in which a pedal lever in the form of a brake pedal is constructed as two separate pieces, a primary lever and a secondary lever pivotally connected by a pivot rod to a deformable part of the body structure of the motor vehicle.
The primary lever is constructed as a ‘U’ section and envelopes the secondary lever. Both of the levers are attached together by a pivot, positioned below a brake booster pushrod and are clamped together by a latching means or catcher. During a crash event there is an interaction of the top of the catcher and another part of the vehicle structure, such as a cross-car beam, that is deformed at a different rate to the part to which the two levers are attached. If the crash is sufficiently severe to cause the beam to contact the catcher then it causes the catcher to pivot around a pivot rod allowing the primary lever to be released from the catcher. As the pivot of the primary and secondary levers is lower than that of the booster pushrod, the primary lever will rotate away from the lower leg of an operator, whereby, upon release, the angle of the pedal plate with respect to the foot of an operator will change rapidly, which may put unwanted stress on the lower leg and foot of the operator.